This invention concerns an internal combustion engine with an electromagnetic actuating mechanism arranged on a cylinder head.
Such an actuating mechanism is known from German patent document DE 197 12 669 A1. Moreover, an electromagnet is arranged between two anchors in an axially spaced construction on the valve tappet. A coil core of the electromagnet has one or more pole surfaces on the respective sides facing the anchors. When the electromagnet is subjected to current, a force acting upon the respective closest anchor predominates. In particular, an alternating motion of the actuating mechanism and consequently an opening and closing of the gas exchange valve coupled with it can be realized in the interaction with the dynamics of the actuating mechanism through an alternating interruption and subjection to the current in the exciter circuit.
The problem in any case with the arrangement of such actuators on cylinder heads is the overall height. When actuating mechanisms are built too high, space problems can arise in the motor area. In particular, problems can arise during motor vehicle assembly and when positioning the motor in the motor space.
For this reason, it is one object of the present invention to specify an internal combustion engine that is compactly constructed to a particular measurement.
This object is reached by the measures specified in claim 1.
Moreover, basic to the invention is the construction of a hollow space in the cylinder head that accommodates a part of the actuating mechanism. This component is mainly, at least in part, the cylinder head side anchor of the actuator unit, whereby the electromagnet lying between the anchors at least partially delimits the hollow space mentioned on the actuator side. Through the formation of the hollow space mentioned above, and by shifting the actuator elements into the hollow space that then becomes possible, the height can be reduced significantly in the direction of the cylinder, which leads to a more compact internal combustion engine overall, especially taking into account the large number of actuator mechanisms to be installed.
Above and beyond this, favorable heat extraction can be attained by directly positioning the electromagnet on the cylinder head so that the actuator can easily be cooled.
In accordance with an advantageous design, the anchor shaft is mounted in the electromagnet itself. In this way, it is important to fix the electromagnet into a position relative to the cylinder head.
The anchor shaft of the actuating mechanism can be indirectly or directly coupled with the valve shaft of the valve, for example, by interposing a valve play compensation element.
In order to utilize the hollow space even better, a first spring (valve spring) should be installed according to an especially advantageous design of the invention. This valve spring can prestress the valve into an end position, for example the closed position. The valve spring is moreover advantageously braced on the valve shaft, on the one hand, and on the cylinder head, on the other. This makes it possible to install the valve in a simple manner.
A second spring (actuator spring) can be incorporated into the actuating mechanism and can be installed far from the cylinder head in relation to the electromagnet. The simple construction of this design is furthered if this actuator unit spring is braced directly against the anchor far from the cylinder head. Through a screw device by means of which the actuator spring can be held above a spring seat, an adjustment of the actuator unit, especially of the two anchor plates, can moreover be conducted with respect to its position toward the electromagnet. The electromagnet can include a coil core with one or more pole surfaces as is known, for example, from German patent document DE 197 12 669 A1.
The present invention will be explained in greater detail below on the basis of a design and with reference to the appended drawings.